Open Carry - Yes, It's Legal
In Pennsylvania, persons 18 years of age and older whom are not prohibited by law from owning firearms may openly carry a handgun in plain sight with no license except in vehicles*, cities of the first class** (Philadelphia) and where prohibited specifically by statute.
Ref.: Title 18, ch.61, Subchapter A. Uniform Firearms Act & Commonwealth v. Ortiz
* Open carry in a vehicle requires a valid PA License to Carry Firearms (LTCF) or a carry license from ANY other state. Ref: Title 18 §6106
** Open carry in a city of the first class requires a valid PA LTCF or a carry license from a reciprocal state. Ref: Title 18 §6108, Title 18 §6106
Carrying concealed (with LTCF) or openly in establishments that serve alcohol is allowed in Pennsylvania.
There is no stipulation in neither the PA code nor case law that a PA LTCF holder must carry concealed. Furthermore, lawful open carry of a firearm is NOT grounds for revocation of a PA LTCF as it is neither an illegal nor dangerous act.